Seafood Safety
Is Something Fishy Going On?
Today’s Dietitian
By Matthew Robb
Vol. 6, No. 11, p. 28

Take heart, fish lovers! Safety concerns are real, but they need not reel in your taste for the fruit de mare.

When New York writer Nancy Peske shops for groceries, her 5-year-old son Dante is foremost in her mind.

Hoping to prepare the most nutritious meals possible, Peske sidesteps the processed foods, bypasses the fatty snacks, ignores the siren song of refined sugars, and instead fills her cart with the freshest ingredients from her favorite Manhattan health food store.

Peske considers herself an informed consumer—that is, until she reaches the seafood counter. A lifelong fish lover, she is baffled by recent advisories warning of mercury and other seafood contaminants. Not knowing whom to trust amid a flurry of diverging opinions, Peske has chosen to essentially abstain.

The decision, she says, wasn’t easy.

“My father was a fisherman. We grew up in Milwaukee and enjoyed fresh fish pulled right from Lake Michigan and other nearby lakes—lots of northern pike and trout.” Pausing to reflect, the 41-year-old continues: “I was always aware of the pollutants that ended up in fish. My father would tell me not to eat the dark meat near the skin. I’ve also edited nutrition books, so I know the key issues. I’m especially concerned because Dante is a growing kid.”

Peske’s dilemma mirrors uneasiness among consumers nationwide. Wanting to eat a delicious product once depicted as a miracle food, today growing numbers of Americans are wondering which species are safe—and which should be avoided even with a 10-foot fishing pole.
Seeking commonsense guidance, we polled a range of experts to get their thoughts on this long-simmering controversy.

Assessing Benefits, Balancing Risks
For Peske and others with elevated cholesterol, saying no to fish may carry its own risks. “I feel like I’m between a rock and a hard place,” she acknowledges. “I know the omega-3 fatty acids are important, but how do I get fish oil into me and my family without getting all those toxins?”

Of particular concern to public interest groups and government regulators is the contaminant mercury, along with polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dioxins. In its organic form—and at high enough exposures—methylmercury is a neurotoxin linked with birth defects, brain damage in children, and serious impairment in adults. According to the British journal The Lancet, human exposure to mercury can be “almost exclusively” linked to fish. Experts trace the pollution “point source” to emissions from power plants and incinerators dotting the globe.

In February, the U.S. Environmental Protection Agency (EPA) estimated that approximately 630,000 children are born each year “at risk for lowered intelligence and learning problems caused by exposure to high levels of mercury in the womb.” The EPA also estimates that roughly 7 million women and children are eating mercury-contaminated fish at or above levels it considers safe. Researchers note that mothers who eat contaminated fish or shellfish pass up to one-half of the “toxic load” to their nursing babies. In February, the FDA reported that newborns often have higher mercury levels than their mothers.

Mercury contamination is found in both recreational (fresh water) and commercial fish. In late August, the EPA reported that a record one-third of U.S. lake waters (14 million acres) and one-quarter of its riverways (850,000 miles) are so tainted with mercury (or other contaminants) that children and pregnant women should reduce eating fish from these sources. Notably, these recreational fish comprise a small percentage of overall U.S. consumption.

Against a backdrop of dueling epidemiologists and squabbling biostatisticians, all parties agree on this: Larger, older predatory fish tend to “bioaccumulate” more mercury than smaller, younger stock. In March, the FDA joined the EPA to caution children and women—specifically women who might become pregnant, are pregnant, or are nursing—to completely avoid the “Big Four”: shark, swordfish, king mackerel, and tilefish. The advisory also cautioned this group to eat only modest amounts of albacore tuna and tuna steak. In February 2003, the British Food Safety Agency explicitly warned this same group that tuna “could present a health hazard.”

Describing fish and shellfish as “an important part of a healthy diet,” the FDA/EPA advisory nevertheless set dietary limits to “reduce exposure to the harmful effects of mercury.” The current government recommendation is that women of childbearing age and young children should eat no more than 12 ounces per week of any type of fish. In Restaurant Land—where 8-ounce adult portions are commonplace—this translates into one to two servings per week for women. On the FDA’s elite “dean’s list” are shrimp, cod, catfish, pollock, trout, and salmon.

Tuna Troubles?
Advocacy groups are particularly concerned about tuna—fresh or canned—because Americans eat lots of it and it continues to fly under most consumers’ radar. Surprisingly, premium albacore (or “white”) tuna contains more mercury than “light” tuna, explaining why the FDA/EPA advisory recommended to women and children no more than 6 ounces per week, or one can. In July, food-safety officials at Consumers Union of U.S., Inc.—publisher of Consumer Reports—recommended that women of childbearing age eat no more than 3 ounces of albacore weekly and young children none. Advocacy groups thus talk of the “Big Five,” saying tuna should be added to the FDA/EPA list because consumers tend to eat oversized portions and because advocates believe keeping one’s mercury exposure below the FDA’s maximum limit is prudent.

Regulators and other researchers, meanwhile, counter that hard scientific data should guide public health advisories and that the FDA/EPA advisory “action levels” factor in a wide safety margin. The U.S. Tuna Foundation goes a step further, asserting that mercury levels in albacore are “well below government standards.” The Consumers Union notes that the U.S. government has set no official safety standards for mercury in albacore or any other fish.

The FDA/EPA landmark March mercury advisory comes on the heels of other key findings. Two of note:

• The journal Science recently reported that cultivated (or “farm-raised”) salmon—especially Atlantic stock—is sufficiently tainted as to possibly nullify any health benefits. Critics respond that the amount of mercury found even in farm-raised salmon is miniscule.

• An August report from the College of William & Mary advises consumers not to be concerned over trace amounts of flame retardants (PBDEs) found in wild and farmed salmon.

Making Sense of It All
Confronted with a riptide of contradictory facts, opinions, and thready suppositions, the layperson is understandably confused, says Melinda Johnson, RD.

As spokesperson for the American Dietetic Association, she counsels, “We should focus on reliable, valid recommendations based on good science, not on one-time uncontrolled studies that make headlines. We shouldn’t scare people away from certain foods.” What worries Johnson is the possibility that consumer overload—a media blitz that whipsaws fish lovers with a confusing “good fish-bad fish” debate—will turn them away from a healthful food source. She adds, “It’s important to wait for the science to catch up with the early claims.”

But according to Jackie Savitz, pollution campaign director and senior scientist for Washington, D.C.-based Oceana, the hard data are available and conclusive. “There are over 2,000 fish advisories for mercury in this country right now,” she says. “The FDA demands a lot of evidence but doesn’t have a systematic, active testing program. When the FDA is willing to issue an advisory—in the face of intense political pressure—you know you really have a problem because it’s survived that regulatory morass.

“Tuna is also a big problem,” Savitz continues. “Few people eat much swordfish, but many people eat tuna every day—people on fixed budgets, people with kids, people who are dieting. The best thing to do is to eat fish lower on the food chain. Avoid the ‘big fish with teeth’—swordfish, shark, king mackerel, tilefish—and tuna. Consumers hear that there are contaminants in seafood and think, ‘Oh, there is nothing that I can eat.’ But there are a lot of different kinds of fish and shellfish out there that are low in contaminants and high in omega-3 fatty acids.” The bottom line, she says, is the need for better regulation, more communication, and less pollution.

“The Great Mimicker”
Dietitian Chuck Balzer, MS, RD, acquired his schooling in mercury the hard way. In late 2001, the lifelong swordfish and tuna fanatic developed a frightening condition. “My legs had this tingling, burning, sometimes shooting-pain sensation—even at rest,” he recalls. As his mystery condition progressed, Balzer began feeling weaker, shakier. When physicians started conducting diagnostic workups for multiple sclerosis, a panicky Balzer started downloading information on disability.

His answer finally arrived in early 2002, when an emergency department physician, acting on a hunch, tested a “twitching” Balzer for mercury poisoning. The lab test detected mercury at roughly five times the upper normal range. After unsuccessful treatment by his general physician, the frantic dietitian opted for controversial intravenous chelation therapy. By summer 2003, he was again mercury-free and biking, walking, and playing beach volleyball.

“Mercury is called ‘the great mimicker,’” Balzer notes. “I suspect lots of people with mercury poisonings are being treated for other disorders. Today, I’m seafood-free and supplement with omega-3 capsules.” Balzer’s personal struggle graphically illustrates why the FDA/EPA placed swordfish on its “hands-off” list.

Eat More Fish?
Nutrition consultant Joyce A. Nettleton, DSc, RD, sees the ocean half-full—maintaining that the risks from contaminants in most seafood types for most people are minimal to nonexistent. Quoting Renaissance physician-surgeon Paracelsus, she says, “It’s the dose that makes the thing a poison.” Consumer advocates agree on this point but debate safety levels.

“If you’re going to encourage people to avoid certain fish or not to eat something that’s as healthful as seafood—which we eat so little of in this country—you better have good grounds for doing so, and those grounds just aren’t there,” she says. “The bottom line is that people are not getting sick from eating too much fish, [but] they are compromising their health from eating too little fish.”

Nettleton, a spokesperson for the tuna industry and author of the 1995 book Omega-3 Fatty Acids and Health, says she supports the FDA/EPA advisory.

“Most data,” she says, “indicate that most people aren’t consuming anything near the amounts [of mercury] that would compromise their health.” She deems it “perfectly safe” for pregnant women to consume up to 12 ounces of canned tuna per week—although the FDA/EPA chose, in its advisory, the more conservative terminology, “reduce exposure to the harmful effects of mercury.” On the topic of wild and farm-raised salmon, she says, “I recommend both without qualification.” She continues, “The levels [of contaminants] found in commonly consumed fish are a fraction of what the World Health Organization and the FDA consider to be safe limits.” Nettleton also points to a recent university study showing ultra-premium “troll-caught albacore,” harvested young from the Pacific Northwest, has much lower mercury levels. A 7.5-ounce can of this “gourmet” product sells online for $3.75.

Simmons College nutrition professor Teresa Fung, ScD, RD, LDN, takes a pragmatic approach. “For nonpregnant, nonlactating adults who only occasionally consume fish,” she says, “I am not concerned about the kind of fish they eat, unless they have other sources of mercury exposure. Frequent fish consumers should look into the FDA mercury advisory. For pregnant, lactating women and young children, they should especially be careful of mercury. Occasional consumption of low-mercury tuna should not be of concern. However, I would err on the side of caution and only consume the other types of tuna on rare occasions.” Expanding her view, she comments, “Fish are an excellent source of omega-3 fatty acids. And salmon is an excellent source of vitamin D.”

Agreed, says Katherine L. Tucker, PhD, professor of nutritional epidemiology at Tufts University in Boston. “My position is that people should eat fatty fish; the benefits outweigh the risks,” she says. “The other side, however, is the risk of PCBs and dioxins that accumulate in these fatty fish.” Tucker points to a colleague’s study that “showed pretty clearly” that farmed salmon have higher contaminant levels than wild salmon. Wild salmon caught in Chile appear safest, followed by Alaska salmon. Trailing behind are Atlantic farm-raised salmon. The problem: contaminated feed. “The very fat that protects our heart and probably our brains is contaminated with PCBs and dioxins,” she says. “The problem is we don’t know who is susceptible to these contaminants, and they are very expensive and difficult to analyze.” In the final analysis, Tucker offers this advice: Eat fish, enjoy fish, but choose wisely.

Fish Oil Supplements
The March 2003 Harvard Health Letter notes that the health value of seafood is mainly derived from the well-studied omega-3 fats: eicosapentaenoic acid and docosahexaenoic acid. Some observers, however, wonder about industry oversight. “[Fish oil capsules are] are an option,” Nettleton says. “But they don’t do anything to improve one’s dietary habits and there’s no assurance … that what you’re buying contains what the label says.”

Savitz disagrees. “Fish oil in capsules is most likely taken from fish lower on the food chain than tuna. Those fish have not bioaccumulated as much as the fish for which the FDA has issued advisories.” She echoes other experts by saying that consumers should not be scared away from the vast smorgasbord of healthful fish and shellfish.

Pulling back from the ensuing debate, what is the take-home message for today’s dietitian?

Avoid the Big Four fish, monitor (and possibly minimize) your intake of tuna, watch for local fish advisories, and enjoy the rest. Our experts underscore the fact that no food—indeed, nothing in life—is risk-free and that fish and shellfish confer vital health benefits to a nation reeling from obesity, heart disease, diabetes, and more.

— Matthew Robb is a freelance writer residing in suburban Washington, D.C.

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